Server/Plugins/ALC: do not require a name attribute

This fixes a bcfg2-lint error. The name attribute at the top level element is not documented and not used, so we should not require it.

Additional to the actually problem, `bcfg2-lint` has another bug. It does not notice this error (only echos error message but return code is 0) because the `FileMonitor` simply catches all exceptions. Maybe we want to add the possibility to reraise the exceptions in `FileMonitor.handle_one_event`.